javascript float from/to bits

Question

I am trying to perform something that is brain-dead simple in any other language but not javascript: get the bits out of float (and the other way around).

In C/C++ it would be something like

float a = 3.1415;
int b = *((int*)&a);

and vise-versa

int a = 1000;
float b = *((float*)&a);

In C# you can use the BitConverter ...floatBits or something alike in Java... Even in VB6 for Christ's sake you can memcpy a float32 into an int32. How on earth can I translate between and int and a float in javascript?

Answer 1

You certainly don't get anything low-level like that in JavaScript. It would be extremely dangerous to allow recasting and pointer-frobbing in a language that has to be safe for untrusted potential-attacker web sites to use.

If you want to get a 32-bit IEEE754 representation of a single-precision value in a Number (which remember is not an int either; the only number type you get in JavaScript is double), you will have to make it yourself by fiddling the sign, exponent and mantissa bits together. There's example code here.